Simply put there was a run and hoarding as a result of concerns first after the election of a pro regulation President and then a second run based on concerns about Congress getting involved. The first run depleted supply, so that the second run created shortages.
Instead of supply being on the store shelves or in distributors or manufacturers warehouse the supply is in peoples basements or garages. I'm not going to rag on anyone that is snapping up supplies well beyond the "normal" amount they keep on hand. I will point out that after the gas crisis back in the 70's someone later figured out that production (supply) was well over actual usage (normal demand) but that much of the supply was in 5 gallon cans in peoples garages or tied up in everyone topping the vehicles fuel tank at every opportunity (hoarding) causing the shortages that did occur, driving more hoarding, creating more shortages.
It was a kind of stupid that the public created their own gas shortage and drove up price, but then again the collection of idiots in DC was not talking about banning private ownership of gasoline either so one could say hoarding ammo or reloading supplies is somewhat more rational but we all as a group live with the consequences of individual choices to snap up everything that we can find.
I generally purchase ammo every year or 18 months, I notice I'm getting low on something, take general inventory, and over the next month or two look for good deals to rebuild stock to the amount I like to keep on hand. Just so happens that this time it coincided with Congress considering legislation so there was not much to buy and nothing that looked like a deal. I figure short of the zombie apocalypse I have enough ammo I can wait a bit.
I also just by chance and bad luck went looking for my first reloading equipment when the run had pretty much any press at a 6 month back order. Now I'm using a Lee loader.... and waiting for all that "like new" equipment to end up on ebay at a good price. Or since the press manufactures have now pretty much caught up I can purchase new. Maybe some of those panic or scarcity driven purchasers of reloading equipment will help grow the community instead of dumping the equipment or stashing it on a shelf. One can hope for a positive outcome right?